可过样例

#include<bits/stdc++.h>
#define ll long long
using namespace std;
int main(){
	ll a,s,f,m,T;
	cin>>a;
	a/=1000;
	f=a%24;
	m=a/60%60;
	s=a/3600%60;
	if(s<10) cout<<0;
	cout<<s<<":";
	if(m<10) cout<<0;
	cout<<m<<":";
	if(f<10) cout<<0;
	cout<<f;
	return 0;
}